notamos
NAXJA Forum User
- Location
- Fort Collins, CO
I bought my XJ w/ 113k on the clock and the engine was toast. The previous owner had let it overheat, cracked the head, warped the crank and ruined the bearings in the process. So, I rebuilt it completely w/ quality parts/proper lubes:
New Melling cam, clevite cam bearings, Clearwater Cylinder Head, melling rockers, pushrods, lifters, pistons, moly rings, clevite main/rod bearings, melling stock oil pump, victor reinz gaskets, header, water pump, 2 row radiator, hoses, belt, timing chain kit, crank, distributor, sensors, etc.
The crank was a stock (not turned) crank from a new 4.0 - pulled by 505 performance for one of their stroker engines. It was polished and within spec when I put it in. So, standard bearings. I plastigauged them and all looked fine according to the FSM. The head was tanked, checked, bored .020 over and honed to fit the new pistons/moly rings.
Since starting this thing for the first time, it has ran perfectly. It sounds perfect, has power, doesn't burn oil, leak, etc. I broke it in properly (started it, took it up to 2000rpms immediately and varied it between 1750 and 2250 for 20 mins, let it cool down and then repeated). I then drained the break-in oil (Pennzoil 10w-30 and COMP Cams 159) and refilled with another bottle of COMP Cams 159 and Pennzoil 10w-30. I waited 1000 miles before changing again. My only concern is oil pressure. Since day one, the HOT idle pressure (when it was in the 90deg range) was around 18psi according to the factory gauge. The cold idle pressure when around 50deg was about 45psi.
Tonight I took off the factory sending unit and installed a mechanical gauge. Here are the details:
After driving it around and getting it nice and hot:
Idle: 18psi
1500rpm: 45psi
2000rpm: 54psi
3000rpm: 58psi
After letting it sit idling for 35mins (with the hood shut) and getting nice and warm (JUST under the 210 mark), the oil pressure was at 15psi exactly.
This is with Pennzoil 10w-30 oil, a bottle of COMP Cams 159 (zinc additive/cam break in additive) and a Napa Gold oil filter.
I'm *tempted* to pull the pan and check the rod bearings just to make sure there is no abnormal wear. I'm also *tempted* to replace the oil pump with either another stock Melling pump or possibly a Melling high volume (not high pressure) pump.
Thoughts/opinions? I am fully aware this is "within spec" but it varies from what I've seen in past 4.0s that I've had. Maybe with 100k on them but not with 1,200 miles on them...
New Melling cam, clevite cam bearings, Clearwater Cylinder Head, melling rockers, pushrods, lifters, pistons, moly rings, clevite main/rod bearings, melling stock oil pump, victor reinz gaskets, header, water pump, 2 row radiator, hoses, belt, timing chain kit, crank, distributor, sensors, etc.
The crank was a stock (not turned) crank from a new 4.0 - pulled by 505 performance for one of their stroker engines. It was polished and within spec when I put it in. So, standard bearings. I plastigauged them and all looked fine according to the FSM. The head was tanked, checked, bored .020 over and honed to fit the new pistons/moly rings.
Since starting this thing for the first time, it has ran perfectly. It sounds perfect, has power, doesn't burn oil, leak, etc. I broke it in properly (started it, took it up to 2000rpms immediately and varied it between 1750 and 2250 for 20 mins, let it cool down and then repeated). I then drained the break-in oil (Pennzoil 10w-30 and COMP Cams 159) and refilled with another bottle of COMP Cams 159 and Pennzoil 10w-30. I waited 1000 miles before changing again. My only concern is oil pressure. Since day one, the HOT idle pressure (when it was in the 90deg range) was around 18psi according to the factory gauge. The cold idle pressure when around 50deg was about 45psi.
Tonight I took off the factory sending unit and installed a mechanical gauge. Here are the details:
After driving it around and getting it nice and hot:
Idle: 18psi
1500rpm: 45psi
2000rpm: 54psi
3000rpm: 58psi
After letting it sit idling for 35mins (with the hood shut) and getting nice and warm (JUST under the 210 mark), the oil pressure was at 15psi exactly.
This is with Pennzoil 10w-30 oil, a bottle of COMP Cams 159 (zinc additive/cam break in additive) and a Napa Gold oil filter.
I'm *tempted* to pull the pan and check the rod bearings just to make sure there is no abnormal wear. I'm also *tempted* to replace the oil pump with either another stock Melling pump or possibly a Melling high volume (not high pressure) pump.
Thoughts/opinions? I am fully aware this is "within spec" but it varies from what I've seen in past 4.0s that I've had. Maybe with 100k on them but not with 1,200 miles on them...
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